Hypomasticus thayeri (Borodin, 1929)

Fig. 3A

Distribution.

Rio Paraíba do Sul and rio Jequitinhonha basins, Brazil.

Diagnosis.

Hypomasticus thayeri differs from H. mormyrops by the upper lip developed; mouth subterminal, not facing down; premaxillary teeth posteriorly oriented and dentary teeth anteriorly oriented when mouth is closed; three anterior teeth of premaxilla and dentary with similar size.